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Martin Fahey looks at the importance of language in sustainability

Net Zero; Carbon Neutral or Carbon negative; Absolute Zero – these are all phrases used in the discussion of sustainability and the goals that are being set.

However, they all mean something slightly different – even though at first glance you may think they are all close enough so must mean the same thing.

The language used when describing sustainability goals is important as these goals are often set now, but have long time horizons for completion.

‘Net Zero by 2050’ for example, looks forward to a date of 2050 as the goal, so it’s important that what is stated is clear and can be backed up by a credible plan that shows a clear path to the goal being detailed.

Below, I take a look at some of the key phrases.

It is no longer enough to make the right noises about protecting the environment and doing your bit

Martin Fahey Green Martin Fahey Head of Sustainability – UK & Ireland

Net Zero

Net Zero is defined as ‘a target of completely negating the amount of greenhouse gases produced by human activity', to be achieved by reducing emissions and implementing methods of absorbing carbon dioxide from the atmosphere.

It is important to understand that achieving Net Zero, requires that emissions are reduced and then when residual emissions remain that these are absorbed from the atmosphere therefore the ‘net’ in the phrase.

Carbon Neutral

Carbon Neutral or Carbon Neutrality is defined as ‘making or resulting in no net release of carbon dioxide into the atmosphere, especially as a result of carbon offsetting.’

This means that a claim of being carbon neutral can be made if an accurate measure of emissions is made which is offset by a credible method of carbon absorption – tree planting is often used as an offsetting method for example although there are many others.

A key way that this differs from the Net Zero definition is that there is no compulsion to reduce emissions to make the claim, an accurate measure of emissions and a commensurate offsetting scheme will allow the claim of neutrality to be made.

Absolute Zero

Absolute Zero is defined as generating no emissions at all. This is not a definition that is used very often.

It is obviously very difficult, if not impossible to operate in a way that generates no emissions, so this phrase is rarely used.

There are other phrases you may see such as ‘Abatement’; ‘Decarbonisation’; ‘Neutralisation’; ‘Near-term science-based targets’ and even ‘Long-term science-based targets’ as can be seen in this brief glossary.


Our understanding of the use of the language used to describe sustainability goals, plans and activity is important.

So important in fact that there is a unique word that has been created specifically for when language is used in a misleading way, ‘greenwash’.

Greenwashing is defined as ‘misleading or deceptive publicity disseminated by an organisation so as to present an environmentally responsible public image’.

Now is not the time for rhetoric, it’s the time for action which is why it is right the people get called out for greenwashing.

While each person or business will start from a different position and be in different places on the road to net zero, the most important thing is that companies have a plan on how they will transition and reduce carbon emissions.

Being seen to be green

Over a decade ago, when we developed out Green Gateway approach to carbon reduction here in the UK, we talked about being ‘Lean, Mean and Green’ and now (as my colleague Chris Newman has identified), companies also now need to be ‘Seen’.

It is no longer enough to make the right noises about protecting the environment and doing your bit.

Now, you have to be able to demonstrate what you are doing and what your ongoing plan is.

And I for one, applaud that.

(The definitions used in this article are taken from Oxford Languages, the English Language dictionaries used by Google, except absolute Zero).

Martin Fahey, Head of Sustainability – UK & Ireland